CN114987442A

CN114987442A - Vehicle control method, vehicle control device, vehicle, and storage medium

Info

Publication number: CN114987442A
Application number: CN202210622768.7A
Authority: CN
Inventors: 牟恒达
Original assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Current assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Priority date: 2022-06-01
Filing date: 2022-06-01
Publication date: 2022-09-02

Abstract

The embodiment of the application provides a vehicle control method and device, a vehicle and a storage medium. The method is applied to a vehicle, the vehicle adopts distributed driving, and the method comprises the following steps: under the condition that the vehicle is monitored to run on a split road surface, acquiring the current actual torque of a first wheel in coaxial wheels of the vehicle; determining a desired torque for a second one of the coaxial wheels based on a current actual torque of the first wheel; the second wheel is controlled to operate at a desired torque for the second wheel. In the embodiment of the application, when the vehicle runs on a specified road condition, the torque for controlling the wheels on the high-side is reduced along with the reduction of the actual torque of the wheels on the low-side, at the moment, the yaw angular acceleration of the vehicle approaches zero, the yaw angular speed cannot be suddenly increased, and the yaw angular speed is always maintained at a lower level, so that the control difficulty of a driver on the vehicle can be reduced, the probability of safety accidents caused by overlarge yaw angular speed is reduced, and the running safety of the vehicle is improved.

Description

Vehicle control method, device, vehicle and storage medium

Technical Field

The present application relates to the field of automotive technologies, and in particular, to a vehicle control method and apparatus, a vehicle, and a storage medium.

Background

Yaw rate refers to the yaw of the vehicle about a vertical axis, the magnitude of which represents the degree of stability of the vehicle. Wherein the larger the yaw rate, the more unstable the vehicle.

When the coaxial wheels of the vehicle travel on the road surface having a large difference in the adhesion coefficient, the wheels on the road surface on the low adhesion coefficient side slip to reduce the torque, and the torque of the wheels on the road surface on the high adhesion coefficient side remains unchanged, so that the yaw rate of the vehicle increases, and the degree of stability of the vehicle decreases.

Disclosure of Invention

The embodiment of the application provides a vehicle control method, a vehicle control device, a vehicle and a storage medium.

In a first aspect, an embodiment of the present application provides a vehicle control method, where the method is applied to a vehicle, and the vehicle adopts distributed driving, and the method includes: under the condition that the vehicle is monitored to run on a split road surface, acquiring the current actual torque of a first wheel in coaxial wheels of the vehicle; determining a desired torque of a second wheel of the coaxial wheels based on a current actual torque of the first wheel, wherein an adhesion coefficient of a road surface traveled by the first wheel is smaller than an adhesion coefficient of a road surface traveled by the second wheel, and the current actual torque of the second wheel is larger than the desired torque of the second wheel; the second wheel is controlled to operate at a desired torque for the second wheel.

In a second aspect, an embodiment of the present application provides a vehicle control apparatus, including: the torque acquisition module is used for acquiring the current actual torque of a first wheel in coaxial wheels of the vehicle under the condition that the vehicle is monitored to run on a split road surface; a torque determination module for determining a desired torque of a second wheel of the coaxial wheels based on a current actual torque of the first wheel, wherein an adhesion coefficient of a road surface traveled by the first wheel is less than an adhesion coefficient of a road surface traveled by the second wheel, and the current actual torque of the second wheel is greater than the desired torque of the second wheel; a control module for controlling the second wheel to operate at a desired torque for the second wheel.

In a third aspect, embodiments of the present application provide a vehicle, where the vehicle includes a processor and a memory, where the memory stores computer program instructions, and the computer program instructions are called by the processor to execute the vehicle control method according to the first aspect.

In a fourth aspect, embodiments of the present application provide a computer-readable storage medium, in which program codes are stored, and the program codes are called by a processor to execute the vehicle control method according to the first aspect.

In a fifth aspect, the present application provides a computer program product, which when executed, can implement the vehicle control method according to the first aspect.

The embodiment of the application provides a vehicle control method, by determining the expected torque of a high-side wheel (namely, a second wheel) based on the actual torque of a low-side wheel (namely, a first wheel) when the vehicle is monitored to run on a specified road condition (coaxial wheels respectively run on a high-adhesion-coefficient road surface and a low-adhesion-coefficient road surface), and then controlling the high-side wheel according to the expected torque of the high-side wheel, because the expected torque of the high-side wheel is smaller than the actual torque of the high-side wheel before control, namely, the torque of the high-side wheel is reduced along with the reduction of the actual torque of the low-side wheel, at the moment, the yaw angular acceleration of the vehicle approaches zero, the yaw angular velocity does not generate an abrupt increase and is always maintained at a lower level, therefore, the control difficulty of a driver on the vehicle can be reduced, and the occurrence probability of safety accidents caused by the overlarge yaw angular velocity is reduced, the driving safety of the vehicle is increased.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of a vehicle provided in the related art running on a split open road.

Fig. 2 is a diagram showing the relationship between torque and vehicle speed, and between yaw rate and vehicle speed when the vehicle provided by the related art runs in a split-open state.

FIG. 3 is a schematic diagram of a vehicle according to an embodiment of the present disclosure traveling in a partially open road.

Fig. 4 is a diagram of the relationship between the torque and the vehicle speed, and the relationship between the yaw rate and the vehicle speed when the vehicle travels in a split open road according to an embodiment of the present application.

FIG. 5 is a schematic illustration of a vehicle provided by an embodiment of the present application.

FIG. 6 is a flow chart of a vehicle control method provided in an embodiment of the present application.

Fig. 7 is a flowchart of a vehicle control method according to another embodiment of the present application.

Fig. 8 is a block diagram of a vehicle control device according to an embodiment of the present application.

FIG. 9 is a functional block diagram of a vehicle provided in an embodiment of the present application.

Fig. 10 is a block diagram of a computer-readable storage medium according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In order to make those skilled in the art better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The following is a description of terms related to embodiments of the present application.

The split road surface: the co-axial wheels of the vehicle travel on a road surface with a large difference in adhesion coefficient. For example, the adhesion coefficient of the road surface traveled by the first wheel of the coaxial wheels is x1, the adhesion coefficient of the road surface traveled by the second wheel of the coaxial wheels is x2, and if the absolute value of the difference between x1 and x2 is greater than the preset adhesion coefficient threshold value a, it is determined that the road surface traveled by the vehicle is open.

Adhesion coefficient: the ratio of the adhesion force to the normal force of the wheels can be approximately considered as the friction coefficient of the road surface, the road surface with higher adhesion coefficient (such as a stone road, an asphalt road and the like) is not easy to slip, the running is safe, the road surface with lower adhesion coefficient (such as a snow ground, an ice surface and the like) is easy to slip, and the potential safety hazard is larger.

Torque: the moment for rotating the object is equal to the product of force and moment arm, and the international unit is Nm.

The inventors have conducted long-term studies and found that, in a vehicle employing distributed drive, when the vehicle is driven on an open road, wheels on the ground with a low adhesion coefficient (hereinafter referred to as low-side wheels) lose grip due to slip, while wheels on the ground with a high adhesion coefficient (hereinafter referred to as high-side wheels) are driven forward with the original torque, and when the vehicle is subjected to yaw force, yaw acceleration and yaw rate are generated, and at this time, it is difficult for a driver to control the vehicle, and the probability of a vehicle safety accident increases.

Referring to fig. 1, there is provided an operation diagram of a vehicle according to the related art. In the case where the vehicle 110 is a four-wheel drive vehicle, the

wheels

111 and 112 run on the ground with a high adhesion coefficient, and the

wheels

113 and 114 run on the ground with a low adhesion coefficient, the vehicle 110 generates yaw acceleration and yaw velocity as shown in the figure, which makes it difficult for the driver to control the vehicle 110.

Referring to fig. 2, a torque-vehicle speed relationship diagram of a vehicle in operation provided by the related art is shown. Where curve 1 represents the driver requested torque, curve 2 represents the actual torque of the high-side wheels, curve 3 represents the actual torque of the low-side wheels, and curve 4 represents the yaw rate of the vehicle. As can be seen from fig. 2, when the vehicle is running on a split open road, the actual torque of the low-side wheels significantly decreases, and with the torque of the high-side wheels remaining unchanged, the vehicle yaw rate significantly increases as the actual torque of the low-side wheels decreases.

In view of the problems in the prior art, the inventors studied a vehicle control method, apparatus, vehicle, and storage medium, by determining a desired torque of a high-side wheel (i.e., a second wheel) based on an actual torque of a low-side wheel (i.e., a first wheel) in a case where it is monitored that the vehicle is running on a specified road condition (coaxial wheels are respectively running on a high-adhesion-coefficient road surface and a low-adhesion-coefficient road surface), and then controlling the high-side wheel according to the desired torque of the high-side wheel, since the desired torque of the high-side wheel is smaller than the actual torque of the high-side wheel before control, that is, the torque of the high-side wheel decreases with a decrease in the actual torque of the low-side wheel, the yaw acceleration of the vehicle approaches zero, the yaw rate does not suddenly increase, and is always maintained at a low level, so that the difficulty of the driver in controlling the vehicle can be reduced, the probability of occurrence of a safety accident due to an excessive yaw rate is reduced, and the driving safety of the vehicle is increased.

Referring to fig. 3, there is provided an operation diagram of a vehicle according to the related art. Wherein the vehicle 310 is a four-wheel drive vehicle, the

wheels

311 and 312 run on the ground with high adhesion coefficient, the

wheels

313 and 314 run on the ground with low adhesion coefficient, the torque of the wheels on the high-side is controlled according to the vehicle control scheme provided by the inventor, at this time, the yaw angular acceleration of the vehicle 310 approaches zero, the yaw angular velocity does not continuously increase, and the vehicle 310 can continue to run normally.

Referring to fig. 4, a torque-vehicle speed relationship diagram of the vehicle during operation is shown according to the embodiment of the present application. Where curve 1 represents the driver requested torque, curve 2 represents the actual torque of the high-side wheels, curve 3 represents the actual torque of the low-side wheels, and curve 4 represents the yaw rate of the vehicle. As can be seen from fig. 4, when the vehicle is running on a split open road, the actual torque of the low-attachment-side wheel is obviously reduced, and when the vehicle control method provided by the embodiment of the present application is used to control the torque of the high-attachment-side wheel, the torque of the high-attachment-side wheel is reduced along with the reduction of the torque of the low-attachment-side wheel, the yaw angular speed of the vehicle is not suddenly increased, and is always maintained at a low level, which is beneficial for the driver to control the vehicle.

Referring to fig. 5, a schematic diagram of a vehicle 500 according to an embodiment of the present application is shown. The vehicle 500 employs distributed drive. The vehicle 500 is an electric vehicle.

In some embodiments, the vehicle 500 is a four-drive vehicle, i.e., four wheels of the vehicle 500 are each controlled using four electric machines. In other embodiments, vehicle 500 is a three-drive vehicle in which the two wheels of the rear axle are controlled using different motors and the two wheels of the front axle are controlled using the same motor.

In the embodiment of the present application, the vehicle 500 has a torque control function, and when the vehicle 500 runs on an opposite-opening road surface, the torque on the high-side is controlled to decrease, so that the yaw rate of the vehicle is prevented from suddenly increasing, the control of the vehicle by the driver is facilitated, the occurrence probability of a safety accident caused by an excessively large yaw rate is reduced, and the running safety of the vehicle 500 is improved. In the embodiment of the present application, the vehicle 500 further has a road condition monitoring function, and monitors whether the vehicle 500 is running in an open circuit.

Referring to fig. 6, a flowchart of a vehicle control method according to an embodiment of the present application is shown. The method is applied to a vehicle and comprises the following steps.

Step S601, in a case that it is monitored that the vehicle runs on a split road surface, acquiring a current actual torque of a first wheel of coaxial wheels of the vehicle.

The split road surface refers to a road surface on which the difference of the adhesion coefficients of the road surfaces driven by two wheels of the coaxial wheels is larger than a first threshold value.

The first threshold value is set experimentally or empirically, and is not limited in the embodiments of the present application. Illustratively, the first threshold is 0.5. In a specific example, the first adhesion coefficient is 0.1, the second adhesion coefficient is 0.8, and the absolute value of the difference between the first adhesion coefficient and the second adhesion coefficient is 0.7, which is greater than the first threshold, and indicates that the vehicle is currently driving on the specified road condition.

The torque is the product of the torque and the distance from the point of application to the direction of application of the torque, and the measuring method comprises at least one of the following steps: strain type torque measurement, piezomagnetic type torque measurement and photoelectric type torque measurement. The embodiment of the present application is only explained by taking an optoelectronic torque measurement method as an example. Specifically, two disc gratings are fixed on a rotating shaft of a first wheel of the vehicle, under the condition that the rotating shaft does not bear torque, light and dark areas of the two gratings are just shielded mutually, no light of a light source penetrates through the gratings to irradiate a photosensitive element, and the photosensitive element does not output signals; under the condition that the rotating shaft bears torque, the rotating shaft deforms to enable the two gratings to generate relative rotation angles, partial light penetrates through the gratings to irradiate the photosensitive element, and the photosensitive element generates output signals. The larger the torque is, the larger the torsion angle is, the larger the luminous flux passing through the grating is, the larger the output signal is, and further, the torque can be calculated according to the output signal of the photosensitive element.

It should be noted that a road surface on which the difference between the adhesion coefficients of the road surfaces traveled by two wheels of the coaxial wheels is smaller than or equal to the first threshold value may be referred to as a uniform road surface. The embodiments of the present application do not provide a matrix control scheme for high-attachment-side wheels in the case where the vehicle is traveling on a uniform road surface.

In step S602, a desired torque for a second wheel of the coaxial wheels is determined based on a current actual torque of the first wheel.

The coefficient of adhesion of the road surface traveled by the first wheel is less than the coefficient of adhesion of the road surface traveled by the second wheel, the current actual torque of the second wheel being greater than the desired torque of the second wheel. The manner in which the desired torque of the second wheel is determined will be explained in the following embodiments.

In the embodiment of the present application, when the vehicle runs on an open road, the vehicle controls the torque of the high-attachment-side wheel (i.e., the second wheel) based on the actual torque of the low-attachment-side wheel (i.e., the first wheel), and specifically, the vehicle controls the torque of the high-attachment-side wheel to decrease with the decrease in the torque of the low-attachment-side wheel, so that the yaw rate of the vehicle does not increase suddenly and is always maintained at a low level, which is beneficial for the driver to control the vehicle, reduces the occurrence probability of safety accidents caused by the yaw rate, and increases the running safety of the vehicle.

In some embodiments, step S602 may instead be implemented as the following sub-steps.

In step S602a, the operating parameters of the first wheel are obtained.

The operating parameter of the first wheel includes at least one of: angular acceleration information of the first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel, and a transmission ratio between the first wheel and the first motor. The first motor is a motor for controlling the first wheel.

The angular acceleration information of the first motor refers to physical quantities describing the magnitude and direction of the angular velocity of the first motor with respect to the time rate of change. In some embodiments, an angular accelerometer is disposed on the first motor to measure angular acceleration information of the first motor. Specifically, the angular accelerometer comprises an angular velocity measuring module and a differentiating circuit, wherein an angular velocity signal of the first motor is measured through the angular velocity measuring module, and the angular acceleration information of the first motor is obtained through differentiating calculation of the measured angular velocity signal through the differentiating circuit.

The rotational inertia information of the first motor is a measure of the inertia (the characteristic of a rotating object to maintain its uniform circular motion or rest) of the first motor as it rotates. The vehicle may measure the rotational inertia information of the first electric machine by at least one of: a three-line pendulum method, a torsional pendulum method, a compound pendulum method, and the like.

The angular acceleration information of the first wheel refers to physical quantities describing the magnitude and direction of the angular velocity of the first wheel with respect to the time rate of change. In some embodiments, an angular accelerometer is disposed on the first wheel to measure angular acceleration information of the first wheel.

The rotational inertia information of the first wheel is a measure of the inertia (the characteristic of a rotating object to maintain its uniform circular motion or rest) of the first wheel as it rotates. The vehicle may measure the moment of inertia information of the first wheel by at least one of: a three-line pendulum method, a torsional pendulum method, a compound pendulum method, and the like.

The transmission ratio refers to the ratio of the angular speeds of the two rotating members in the mechanism, and the transmission ratio between the first wheel and the first motor is also the ratio between the angular speed of the first wheel and the angular speed of the first motor. In some embodiments, angular velocity sensors are provided on the first motor and the first wheel, respectively, an angular velocity of the first motor is measured by the angular velocity sensor provided on the first motor, an angular velocity of the first wheel is measured by the angular velocity sensor provided on the first wheel, and then a ratio between the angular velocity of the first wheel and the angular velocity of the first motor is determined as a transmission ratio between the first wheel and the first motor.

In step S602b, a loss value is determined based on the operating parameter of the first wheel.

The current actual torque of the first wheel is lost at both the first motor and the first wheel, and to quantify this loss, the vehicle determines a loss value based on an operating parameter of the first wheel.

In some embodiments, step S602b may instead be implemented as the following sub-steps: determining a product between angular acceleration information of the first motor and rotational inertia information of the first motor as a first loss component; determining a product between angular acceleration information of the first wheel and rotational inertia information of the first wheel as an intermediate value, and determining a transmission ratio of the intermediate value and the first wheel as a second loss component; the sum of the first loss component and the second loss component is determined as a loss value.

The first loss component, i.e. the moment of momentum of the first electric machine, is a quantity describing the state of rotation of the first electric machine. The intermediate value, i.e. the moment of momentum of the first wheel, is a quantity describing the rotational state of the first wheel.

Step S602c, obtaining the current actual torque, the loss value and the preset compensation value of the first wheel to determine the expected torque of the second wheel.

The vehicle determines the sum of the specified difference, i.e. the difference between the current actual torque of the first wheel and the loss value, and the preset compensation value as the desired torque of the second wheel. The preset compensation value is a deviation value determined based on the speed of the vehicle and the yaw-rate variation, which is set experimentally or empirically.

In some embodiments, the desired torque of the second wheel is calculated by the following calculation.

Wherein M is _H Refers to the desired torque of the second wheel, M _L Is the current actual torque of the first wheel, d _mot Angular acceleration information, J, of the first motor _mot Is the rotational inertia information of the first motor, d _wheel Angular acceleration information of the first wheel, J _wheel The rotational inertia information of the first wheel is referred to, ikin is a transmission ratio, and offset is a preset compensation value.

Step S603, controlling the second wheel to operate according to the desired torque of the second wheel.

In summary, according to the technical solution provided by the embodiments of the present application, when it is monitored that the vehicle is running on a specified road condition (where coaxial wheels respectively run on a road surface with a high adhesion coefficient and a road surface with a low adhesion coefficient), the vehicle determines the expected torque of the high-side wheels (i.e. the second wheels) based on the actual torque of the low-side wheels (i.e. the first wheels), and then controls the high-side wheels according to the expected torque of the high-side wheels, because the expected torque of the high-side wheels is smaller than the actual torque of the high-side wheels before control, that is, the torque of the high-side wheels decreases with the decrease of the actual torque of the low-side wheels, at this time, the yaw acceleration of the vehicle approaches zero, the yaw velocity does not increase suddenly, and is always maintained at a low level, the difficulty of the driver in controlling the vehicle can be reduced, and the probability of occurrence of a safety accident caused by an excessively large yaw velocity can be reduced, the driving safety of the vehicle is increased.

Referring to fig. 7, a flowchart of a vehicle control method according to an embodiment of the disclosure is shown. The method is applied to a vehicle and comprises the following steps.

In step S701, when it is monitored that the vehicle is running on an opposite road surface, information on the yaw rate of the vehicle is acquired.

The yaw-rate information is used to characterize the yaw-rate acceleration of the vehicle and the yaw-rate of the vehicle.

The yaw rate of the vehicle is the yaw of the vehicle about the vertical axis, the magnitude of the yaw representing the degree of stability of the vehicle, the greater the yaw rate of the vehicle, the less stable the vehicle, and the smaller the yaw rate of the vehicle, the more stable the vehicle.

The yaw acceleration of the vehicle is used to determine the phase at which the yaw rate is. When the yaw angular acceleration of the vehicle is larger than zero, the yaw angular speed is in an acceleration stage; in the case that the yaw angular acceleration of the vehicle is less than zero, the yaw angular velocity is in a deceleration stage; in the case where the yaw angular acceleration of the vehicle is equal to zero, it is said that the yaw angular velocity is in uniform motion.

In some embodiments, a yaw-rate accelerometer is provided on the vehicle to measure yaw-rate acceleration information. Specifically, the yaw-rate accelerometer comprises a yaw-rate measuring module and a differentiating circuit, wherein a yaw-rate signal of the vehicle is measured through the yaw-rate measuring module, and the measured yaw-rate signal is subjected to differential calculation through the differentiating circuit to obtain yaw-rate acceleration information.

In step S702, the current actual torque of the first wheel is acquired in the case where the yaw rate information of the vehicle satisfies the preset condition.

The preset conditions include: the yaw velocity is greater than a first preset value; or/and the yaw angular acceleration is larger than a second preset value. The first preset value is set according to experiments or experiences, and the second preset value is used for representing that the yaw rate is in an acceleration stage. Illustratively, the first preset value is 8 and the second preset value is 0.

In the embodiment of the present application, by executing the subsequent torque control step for the high-side wheels in the case where the yaw-rate information satisfies the preset condition, the power consumption of the vehicle can be saved.

In step S703, a desired torque of the second wheel is determined based on the current actual torque of the first wheel.

The current actual torque of the second wheel is greater than the desired torque of the second wheel.

In step S704, a control period is determined according to the yaw rate.

The control period has a positive correlation with the yaw rate. That is, the larger the yaw rate is, the longer the control period is; the smaller the yaw rate, the shorter the control period.

In some embodiments, the vehicle looks up a control period corresponding to the yaw rate in a first map including a mapping relationship between the yaw rate and the control period. The first mapping table may be set according to an experiment or experience, specifically, in the first experiment stage, the first mapping table is set by a technician according to an experience, and the iteration may be performed on the first mapping table according to an experiment result in a subsequent experiment process. In further exemplary embodiments, the vehicle is determining the control period by a first functional relationship characterizing the functional relationship between yaw rate and control period, which can be fitted from experimental data, and the yaw rate.

Step S705 controls the second wheel to operate at a desired torque of the second wheel for a control period.

The time length of the control period is a control duration. In the embodiment of the present application, the control accuracy can be improved by determining the control period based on the yaw rate.

And step S706, controlling the torque of the second wheel to increase after the control time interval is ended.

Wherein the amount of increase per unit time in the torque of the second wheel is in a negative correlation with the yaw rate. That is, the larger the yaw rate is, the smaller the increase amount per unit time of the torque of the second wheel is; the smaller the yaw rate is, the larger the increase amount per unit time of the torque of the second wheel is.

In some embodiments, the vehicle looks up the amount of increase per unit time in torque of the second wheel corresponding to the yaw rate in a second map, which includes a mapping relationship between the yaw rate and the amount of increase per unit time in torque of the second wheel. The second mapping table may be set according to an experiment or experience, specifically, in the first experiment stage, the second mapping table is set by a technician according to an experience, and the second mapping table may be iterated according to an experiment result in a subsequent experiment process. In other embodiments, the vehicle determines the increase in torque per unit time of the second wheel by a second functional relationship characterizing the functional relationship between yaw rate and the increase in torque per unit time of the second wheel and yaw rate, which can be fitted from experimental data.

Through the mode, under the condition of controlling the torque of the high-side wheels, the torque of the high-side wheels is allowed to be gradually increased according to the magnitude of the yaw velocity, and the requirement of a driver on the acceleration performance of the vehicle is met on the premise of ensuring the running safety of the vehicle.

In step S707, the second wheel is controlled to operate in accordance with the increased torque of the second wheel.

In summary, according to the technical scheme provided by the embodiment of the application, the subsequent torque control step for the high-side wheels is executed under the condition that the yaw rate information meets the preset condition, so that the situation that the vehicle provides torque control for the high-side wheels under the unnecessary condition can be avoided, the power consumption of the vehicle is effectively saved, the control duration for the torque of the high-side wheels is determined according to the yaw rate, the control precision is improved, the torque of the high-side wheels is controlled to be gradually increased according to the yaw rate after the control duration is ended, and the requirement of the driver on the acceleration performance of the vehicle is met on the premise of ensuring the driving safety of the vehicle.

The embodiment of the application provides a torque control scheme for the wheels on the high-attachment side aiming at the specified road condition when the vehicle runs, and the vehicle needs to be ensured to run under the specified road condition in order to improve the control precision. An embodiment of monitoring whether a vehicle is traveling under a specified road condition is described below.

In some embodiments, the vehicle monitors whether the vehicle is traveling on a split-road surface by: obtaining the slip rates respectively corresponding to coaxial wheels of the vehicle, wherein the slip rates respectively corresponding to the coaxial wheels comprise a first slip rate and a second slip rate; in the case where the absolute value of the difference between the first slip ratio and the second slip ratio is larger than the second threshold value, it is determined that the vehicle is running on a split road.

Under the condition that the vehicle is a four-motor-driven vehicle, the vehicle can acquire the slip rates respectively corresponding to the front-shaft wheels, can also acquire the slip rates respectively corresponding to the rear-shaft wheels, and can also acquire the slip rates respectively corresponding to the front-shaft wheels and the slip rates respectively corresponding to the rear-shaft wheels. Under the condition that the vehicle is a three-motor driven vehicle, the vehicle can obtain the slip rates corresponding to the wheels of the rear axle respectively.

When the wheel sends out traction force or braking force, relative motion can occur between the wheel and the ground, wherein the slip rate of the wheel is used for representing the proportion of a sliding component in the motion of the wheel. The larger the slip ratio of the wheel is, the smaller the adhesion coefficient of the road surface on which the wheel is running is, and the smaller the slip ratio of the wheel is, the larger the adhesion coefficient of the road surface on which the wheel is running is.

In some embodiments, a wheel speed sensor is provided on a wheel of the vehicle for detecting a wheel speed, and the slip ratio of the wheel is calculated by the following calculation formula after the wheel speed and the vehicle speed are acquired by the vehicle.

Wherein u represents a vehicle speed, u _w Representing wheel speed and s representing slip rate.

In other embodiments, a wheel of the vehicle is provided with an angular velocity sensor for detecting an angular velocity of the wheel, and the vehicle calculates a slip ratio of the wheel by the following calculation formula after acquiring the angular velocity of the wheel and a vehicle speed.

Where u represents the vehicle speed, w represents the angular velocity of the wheel, and r represents the radius of the wheel. s represents a slip ratio.

The absolute value of the difference between the slip ratios respectively corresponding to the coaxial wheels can be calculated by the following mathematical formula.

y＝|y1-y2|。

Where y1 represents a first slip ratio among the slip ratios corresponding to the coaxial wheels, respectively, and y2 represents a second slip ratio among the slip ratios corresponding to the coaxial wheels, respectively.

The second threshold value is set experimentally or empirically, and is not limited in the embodiments of the present application. Illustratively, the second threshold is 1. In a specific example, the first slip ratio is 3.6, the second slip ratio is 4.7, the absolute value of the difference between the first slip ratio and the second slip ratio is 1.1, and the difference is larger than the second threshold value, which indicates that the vehicle is currently running on a split road.

In some embodiments, the vehicle acquires the slip rates corresponding to the coaxial wheels respectively at preset time intervals so as to ensure real-time monitoring of the vehicle. The preset time may be set according to experiments or experience, and is not limited in the embodiments of the present application. Illustratively, the preset time is 5 seconds. In other embodiments, the vehicle acquires respective slip rates of the coaxial wheels in the case where it is detected that the yaw acceleration is greater than a preset value. The preset value is used to characterize the yaw rate in the acceleration phase. Optionally, the preset value is zero. Under the normal condition, when the vehicle runs on the specified road condition, the yaw velocity can be increased, and the yaw acceleration is greater than zero at the moment, so that the condition that the yaw acceleration is greater than zero is monitored, the condition that the vehicle runs on the split road surface at a high probability is indicated, whether the vehicle runs on the split road surface is monitored at the moment, and the problem of high power consumption caused by continuous monitoring is avoided.

After it is determined that the vehicle is running on the split-open road surface, if the first slip ratio is smaller than the second slip ratio, the wheel with the first slip ratio is determined as the second wheel, and the wheel with the second slip ratio is determined as the first wheel; and if the first slip ratio is larger than the second slip ratio, determining the wheel with the first slip ratio as the first wheel, and determining the wheel with the second slip ratio as the second wheel.

In other embodiments, after obtaining the slip rates respectively corresponding to the coaxial wheels, the vehicle searches for an adhesion coefficient corresponding to the first slip rate and an adhesion coefficient corresponding to the second slip rate in a mapping table between the slip rates and the adhesion coefficients, then detects whether an absolute value of a difference between the slip rates and the adhesion coefficients is greater than a first threshold, if the absolute value of the difference between the slip rates and the adhesion coefficients is greater than the first threshold, it indicates that the vehicle is running on an open road, and if the absolute value of the difference between the slip rates and the adhesion coefficients is less than or equal to the first threshold, it indicates that the vehicle is not running on the open road. The mapping table between the slip ratio and the adhesion coefficient may be preset according to experiments or experience, and the embodiment of the present application does not limit this.

Referring to fig. 8, a block diagram of a vehicle control device 800 according to an embodiment of the present disclosure is shown. The device is applied to a vehicle which adopts distributed driving, and the vehicle control device 800 comprises: a torque acquisition module 810, a torque determination module 820, and a control module 830.

The torque obtaining module 810 is configured to obtain a current actual torque of a first wheel of coaxial wheels of the vehicle when the vehicle is monitored to be driven on a split road. A torque determination module 820 for determining a desired torque for a second wheel of the coaxial wheels based on a current actual torque of the first wheel, wherein an adhesion coefficient of a road surface traveled by the first wheel is less than an adhesion coefficient of a road surface traveled by the second wheel, and the current actual torque of the second wheel is greater than the desired torque of the second wheel. A control module 830 for controlling the second wheel to operate at a desired torque for the second wheel.

In some embodiments, the torque determination module 820 is configured to obtain an operating parameter of a first wheel, the operating parameter of the first wheel including at least one of: angular acceleration information of the first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel, and a transmission ratio of the first wheel; wherein the first motor is a motor for controlling the first wheel; determining a loss value based on an operating parameter of the first wheel; and acquiring the current actual torque, the loss value and the preset compensation value of the first wheel to determine the expected torque of the second wheel.

In some embodiments, the torque determination module 820 is configured to determine a product between angular acceleration information of the first motor and rotational inertia information of the first motor as a first loss component; determining a product between angular acceleration information of the first wheel and rotational inertia information of the first wheel as an intermediate value, and determining a transmission ratio of the intermediate value and the first wheel as a second loss component; the sum of the first loss component and the second loss component is determined as a loss value.

In some embodiments, the torque obtaining module 810 is configured to obtain yaw rate information of the vehicle when the vehicle is monitored to be driven on the specified road condition, where the yaw rate information is used to represent a yaw acceleration of the vehicle and a yaw rate of the vehicle; under the condition that the yaw velocity information of the vehicle meets a preset condition, acquiring the current actual torque of a first wheel; wherein the preset conditions include: the yaw angular speed is greater than a first preset value; or/and the yaw angular acceleration is larger than a second preset value.

In some embodiments, the control module 830 is configured to: determining a control time length according to the yaw rate, wherein the control time length and the yaw rate have positive correlation; and controlling the second wheel to work according to the expected torque of the second wheel in a control period, wherein the time length of the control period is a control time length.

In some embodiments, the torque determination module 820 is further configured to control the torque of the second wheel to increase after the end of the control period, wherein the amount of increase per unit time in the torque of the second wheel is inversely related to the yaw rate. And a control module 830 for controlling the second wheel to operate according to the increased torque of the second wheel.

In some embodiments, the apparatus further comprises: a road condition monitoring module (not shown). The road condition monitoring module is used for acquiring the slip rates respectively corresponding to the coaxial wheels of the vehicle, wherein the slip rates respectively corresponding to the coaxial wheels comprise a first slip rate and a second slip rate; in a case where the absolute value of the difference between the first slip ratio and the second slip ratio is larger than a second threshold value, it is determined that the vehicle is running on a split road.

It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses and modules may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In several embodiments provided in the present application, the coupling of the modules to each other may be electrical, mechanical or other forms of coupling.

In addition, functional modules in the embodiments of the present application may be integrated into one processing module, or each of the modules may exist alone physically, or two or more modules are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode.

As shown in fig. 9, the present example also provides a vehicle 900, where the vehicle 900 includes a processor 910, a memory 920, and at least one lidar 930. Wherein memory 920 stores computer program instructions.

Processor 910 may include one or more processing cores. The processor 910 interfaces with various components throughout the battery management system using various interfaces and lines to perform various functions of the battery management system and to process data by executing or executing instructions, programs, code sets, or instruction sets stored in the memory 920 and invoking data stored in the memory 920. Alternatively, the processor 910 may be implemented in hardware using at least one of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor 910 may integrate one or more of a Central Processing Unit (CPU) 910, a Graphics Processing Unit (GPU) 910, a modem, and the like. Wherein, the CPU mainly processes an operating system, a user interface, an application program and the like; the GPU is used for rendering and drawing display content; the modem is used to handle wireless communications. It is understood that the modem may not be integrated into the processor 910, but may be implemented by a communication chip.

The Memory 920 may include a Random Access Memory (RAM) or a Read-Only Memory (Read-Only Memory) 920. The memory 920 may be used to store an instruction, a program, code, a set of codes, or a set of instructions. The memory 920 may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for implementing at least one function (such as a touch function, a sound playing function, an image playing function, etc.), instructions for implementing various method examples described below, and the like. The data storage area may also store data created by the vehicle in use (such as a phone book, audio and video data, chat log data), and the like.

Referring to fig. 10, a computer-readable storage medium 1000 is further provided according to an embodiment of the present application, where the computer-readable storage medium 1000 stores computer program instructions 1010, and the computer program instructions 1010 can be called by a processor to execute the method described in the foregoing embodiment.

The computer-readable storage medium 1000 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. Alternatively, the computer-readable storage medium 1000 includes a non-volatile computer-readable storage medium. The computer readable storage medium 1000 has storage space for computer program instructions 1010 for performing any of the method steps S of the method described above. The computer program instructions 1010 may be read from or written to one or more computer program products. The computer program instructions 1010 may be compressed in a suitable form.

Although the present application has been described with reference to preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application, and all changes, substitutions and alterations that fall within the spirit and scope of the application are to be understood as being covered by the following claims.

Claims

1. A vehicle control method, applied to a vehicle that employs distributed driving, comprising:

under the condition that the vehicle is monitored to run on a split road surface, acquiring the current actual torque of a first wheel in coaxial wheels of the vehicle;

determining a desired torque for a second wheel of the coaxial wheels based on a current actual torque of the first wheel, wherein a coefficient of adhesion of a road surface traveled by the first wheel is less than a coefficient of adhesion of a road surface traveled by the second wheel, and wherein the current actual torque of the second wheel is greater than the desired torque of the second wheel;

controlling the second wheel to operate at a desired torque for the second wheel.

2. The method of claim 1, wherein determining the desired torque for a second wheel of the coaxial wheels based on a current actual torque of the first wheel comprises:

obtaining operating parameters of the first wheel, the operating parameters of the first wheel including at least one of: angular acceleration information of a first motor, rotational inertia information of the first motor, angular acceleration information of the first wheel, rotational inertia information of the first wheel, and a transmission ratio between the first wheel and the first motor; wherein the first motor is a motor for controlling the first wheel;

determining a loss value based on an operating parameter of the first wheel;

and acquiring the current actual torque of the first wheel, the loss value and a preset compensation value to determine the expected torque of the second wheel.

3. The method of claim 2, wherein determining a loss value based on an operating parameter of the first wheel comprises:

determining a product between angular acceleration information of the first motor and rotational inertia information of the first motor as a first loss component;

determining a product between angular acceleration information of the first wheel and rotational inertia information of the first wheel as an intermediate value, and determining a transmission ratio of the intermediate value and the first wheel as a second loss component;

determining a sum of the first loss component and the second loss component as the loss value.

4. The method of claim 1, wherein said obtaining a current actual torque of a first wheel of the coaxial wheels of the vehicle in the event that the vehicle is monitored to be traveling on a split road comprises:

under the condition that the vehicle is monitored to run on a specified road condition, acquiring yaw rate information of the vehicle, wherein the yaw rate information is used for representing the yaw acceleration of the vehicle and the yaw rate of the vehicle;

acquiring the current actual torque of the first wheel under the condition that the yaw velocity information of the vehicle meets a preset condition;

wherein the preset conditions include: the yaw angular speed is greater than a first preset value; or/and the yaw angular acceleration is larger than a second preset value.

5. The method of claim 4, wherein said controlling said second wheel to operate at a desired torque for said second wheel comprises:

determining a control time period according to the yaw rate, wherein the control time period is in positive correlation with the yaw rate;

and controlling the second wheel to work according to the expected torque of the second wheel in a control period, wherein the time length of the control period is the control time length.

6. The method of claim 5, wherein after controlling the second wheel to operate at the desired torque for the second wheel for the control period, further comprising:

controlling the torque of the second wheel to increase after the control period ends, wherein the increase of the torque of the second wheel per unit time is in a negative correlation with the yaw rate;

and controlling the second wheel to work according to the increased torque of the second wheel.

7. The method according to any one of claims 1 to 6, further comprising:

obtaining the slip rates respectively corresponding to the coaxial wheels, wherein the slip rates respectively corresponding to the coaxial wheels comprise a first slip rate and a second slip rate;

determining that the vehicle is traveling on the split road surface in a case where an absolute value of a difference between the first slip ratio and the second slip ratio is larger than a second threshold value.

8. A vehicle control apparatus, characterized in that the apparatus comprises:

the torque acquisition module is used for acquiring the current actual torque of a first wheel in coaxial wheels of the vehicle under the condition that the vehicle is monitored to run on a split road surface;

a torque determination module configured to determine a desired torque of a second wheel of the coaxial wheels based on a current actual torque of the first wheel, wherein an adhesion coefficient of a road surface traveled by the first wheel is less than an adhesion coefficient of a road surface traveled by the second wheel, and the current actual torque of the second wheel is greater than the desired torque of the second wheel;

a control module for controlling the second wheel to operate at a desired torque for the second wheel.

9. A vehicle comprising a processor, a memory storing computer program instructions that are invoked by the processor to perform a vehicle control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that a program code is stored in the computer-readable storage medium, which is called by a processor to execute a vehicle control method according to any one of claims 1 to 7.